The present invention relates to a bandwidth control method of packet data in a packet switching network and a packet switching network system.
Packet transfer technique in a conventional fixed network can be divided into the following two types of packet communications methods.
[1] Common path multiplex communications method.
[2] Individual path communications method.
The common path multiplex communications method installs between packet switching nodes transmission links common to a plurality of packet users in advance, and multiplexes into the common links packets which include address information of individual users, thereby transferring the packets between the nodes. Extracting the packets from the common links, a receiving node refers to the addresses of the individual users, and multiplexes again into the common links of the output transmission paths corresponding to the addresses. Thus, the user packets are successively transferred to a destination node, and then to destination party terminals.
As an example of the common path multiplex method, there is a method such as packet switching or frame relay, which usually multiplexes the user packets into physical links with a particular bandwidth. In the ATM (Asynchronous Transfer Mode) transmission, there is a method of multiplexing user packets into VP (Virtual path) links with a particular bandwidth, or into VC (Virtual Channel) links as in AAL-2 (ATM Adaptation Layer type 2), in which case, equipment for multiplexing into the common links usually uses FIFO without carrying out bandwidth assurance.
The individual path communications method establishes between the packet switching nodes transmission links with their bandwidth assured for individual packet users, thereby carrying out routing.
The packet switching nodes each execute witching so that individual link is established between the nodes for each user, thus extending to the destination party terminals.
As a typical example of the individual path communications method, there is a packet communication method employing STM (Synchronous Transfer Mode) transmission or bandwidth assured ATM transmission.
Considering the two packet communications methods, the common path multiplex communications method possesses an advantage of a high transmission efficiency because a plurality of users can utilize the bandwidth of a particular set of common packet links in a statistically multiplexed manner. The common path multiplex communications method, however, can offer only best-efforts services because the packet communication rates of individual users are restricted by the communication state of the other users multiplexed into the same common packet links.
The individual path communications method is just the opposite of the common path multiplex communications method, offering an advantage of being able to assure the communications bandwidths of the individual users because of a dedicated packet link provided to each user. However, it has an disadvantage of impairing the transmission efficiency because the resources assigned to the individual users are unavailable to the other users, and particularly because the division loss takes place in the variable rate transmission in which the resources are assigned in such a manner that the users have the maximum bandwidth each.
As described above, the conventional common path multiplex communications method has a disadvantage that the packet communication rates of individual users are restricted by the communication state of the other users because of the multiplexing into the same common packet links. In contrast with this, although the individual path communications method assures the communications bandwidths of the individual users, it has a disadvantage of impairing the transmission efficiency because the resources assigned to the individual users are unavailable to the other users.
The present invention was achieved to solve the foregoing problems. Therefore, it is an object of the present invention to provide a bandwidth control method of packet data in a packet switching network and a packet switching network system that can ensure desired bandwidths for the users by switching between bandwidth-assured transmission connections and bandwidth-unassured transmission connections, and that can efficiently operate the transmission paths in the network.
In the first aspect of the present invention, there is provided a bandwidth control method of packet data in a packet switching network for switching, in a packet switching network for transmitting packet data, a transmission connection for transmitting the packet data, the bandwidth control method comprising:
a monitoring step of monitoring a communication traffic volume of the packet data in the packet switching network; and
a switching step of switching, in response to a result obtained by comparing the communication traffic volume with a predetermined threshold value, the transmission connection between a bandwidth-assured transmission connection which ensures a communication bandwidth for each user terminal equipment transmitting the packet and a bandwidth-unassured transmission connection which does not ensure the communication bandwidth.
Here, the packet switching network may be an ATM switching network, the bandwidth-assured transmission connection which ensures the communication bandwidth for each user terminal equipment transmitting the packet may be a connection established in a VC in an individual VP or in an individual VC group, and the bandwidth-unassured transmission connection may be a connection established in a VC in a common VP or in a common VC group;
the monitoring step may monitor the communication traffic volume of the packet data of the user terminal equipment in the ATM switching network; and
the switching step may switch, in response to the result obtained by comparing the communication traffic volume of the packet data of the user terminal equipment with the predetermined threshold value, the transmission connection used by the user terminal equipment between the VC in the individual VP or in the individual VC group and the VC in the common VP or in the common VC group.
The monitoring step may comprise a measuring step of measuring the communication traffic volume; and
the switching step may comprise the steps of:
comparing, when the connection of the user terminal equipment is the VC in the individual VP or in the individual VC group, the communication traffic volume obtained at the monitoring step with a first predetermined threshold value, and issuing, when the communication traffic volume is less than the first predetermined threshold value, a command to change the connection used by the user terminal equipment from the VC in the individual VP or in the individual VC group to the VC in the common VP or in the common VC group;
comparing, when the connection used is the VC in the common VP or in the common VC group, the communication traffic volume obtained at the monitoring step with a second predetermined threshold value, and issuing, when the communication traffic volume is greater than the second predetermined threshold value, a command to change the connection used by the user terminal equipment from the VC in the common VP or in the common VC group to the VC in the individual VP or in the individual VC group; and
changing the connection used by the user terminal equipment in response to the commands of the steps of issuing the commands to change.
The monitoring step may further comprise a common VP or common VC group bandwidth monitoring step of measuring during communications a total traffic volume of users in the common VP or in the common VC group, or of measuring an idle capacity in the common VP or in the common VC group; and
the switching step may further comprise a step of changing, when a result of the common VP or common VC group bandwidth monitoring step indicates that the bandwidth of the common VP or of the common VC group tightens, the connection of a user whose traffic is rather heavy in the common VP from the VC in the common VP or in the common VC group to the VC in the individual VP or in the individual VC group.
The ATM switching network may be a mobile network comprising a base station to which the user terminal equipment is connected, a switching center to which the base station is connected, a gateway center to which the switching center is connected, and terminal equipment of an external network connected to the gateway center, and wherein the bandwidth control method may further comprise the steps of:
establishing, when the user terminal equipment originates an outgoing call, a connection in the VC in the individual VP or individual VC group, or in the VC in the common VP or in the common VC group, between the base station in a visitor location of the user terminal equipment and the gateway center through the switching center; and
establishing, when the user terminal equipment terminates an incoming call, a connection in the VC in the individual VP or individual VC group, or in the VC in the common VP or in the common VC group, between the gateway center and the base station to which the user terminal equipment is connected in accordance with a location of the user terminal equipment, the location being registered by the user terminal equipment.
The step of measuring the communication traffic volume may start a new measurement when the visitor location base station is changed by roaming of the user terminal equipment.
A VC in the common VP or in the common VC group may be used when originating an outgoing call from the user terminal equipment, or when terminating an incoming call from an external ATM switching network.
In the second aspect of the present invention, there is provided a packet switching network system for switching, in a packet switching network for transmitting packet data, a transmission connection for transmitting the packet data, the packet switching network system comprising:
monitoring means for monitoring a communication traffic volume of the packet data in the packet switching network; and
switching means for switching, in response to a result obtained by comparing the communication traffic volume with a predetermined threshold value, the transmission connection between a bandwidth-assured transmission connection which ensures a communication bandwidth for each user terminal equipment transmitting the packet and a bandwidth-unassured transmission connection which does not ensure the communication bandwidth.
Here, the packet switching network may be an ATM switching network, the bandwidth-assured transmission connection which ensures the communication bandwidth for each user terminal equipment transmitting the packet may be a VC in an individual VP or in an individual VC group, and the bandwidth-unassured transmission connection may be a VC in a common VP or in a common VC group, and wherein the packet switching network system comprises:
monitoring means for monitoring the communication traffic volume of the packet data of the user terminal equipment in the ATM switching network; and
packet switching means for processing the packet data of the user terminal equipment, the packet switching means switching, in response to the communication traffic volume, the transmission connection used by the user terminal equipment between the VC in the individual VP or in the individual VC group and the VC in the common VP or in the common VC group.
The monitoring means may comprise:
measuring means for measuring the communication traffic volume of the packet data of the user terminal equipment;
state managing means for holding, for each user terminal equipment, VP or VC group types used by the user terminal equipment; and
change direction means for comparing, when the connection type of the user terminal equipment the state managing means holds is the individual VP or the individual VC group, the communication traffic volume with a first predetermined threshold value, and issuing, when the communication traffic volume is less than the first predetermined threshold value, a command to change a connection setting used by the user terminal equipment from the VC in the individual VP or in the individual VC group to the VC in the common VP or in the common VC group, and comparing, when the connection type of the user terminal equipment the state managing means holds is the common VP or in the common VC group, the communication traffic volume with a second predetermined threshold value, and issuing, when the communication traffic volume is greater than the second predetermined threshold value, a command to change the connection setting used by the user terminal equipment from the VC in the common VP or in the common VC group to the VC in the individual VP or in the individual VC group, and wherein
the packet switching means may comprise means for changing the connection-used by the user terminal equipment in response to the commands of the change direction means.
The monitoring means may further comprise common VP or common VC group bandwidth monitoring means for measuring during communications a total traffic volume of users in the common VP or in the common VC group, or for measuring an idle capacity in the common VP or in the common VC group; and
the packet switching means may further comprise means for changing, when a result of the common VP or common VC group bandwidth monitoring means indicates that the bandwidth of the common VP or of the common VC group tightens, the connection of a user whose traffic is rather heavy in the common VP from the VC in the common VP or in the common VC group to the VC in the individual VP or in the individual VC group.
The ATM switching network may-be a mobile network comprising:
a gateway center for connecting the ATM switching network with an external ATM switching network, and for identifying user terminal equipment of the ATM switching network from packet data sent from the external network; and
service control means for location registration of the user terminal equipment, and wherein
the packet switching means may further comprise means for establishing, from a location provided from the service control means, in the VC in the individual VP or individual VC group, or in the VC in the common VP or in the common VC group, a connection between a base station connected to the user terminal equipment and the gateway center in the ATM switching network.
The means for measuring the communication traffic volume may comprise means for starting a new measurement when the visitor location base station is changed by roaming of the user terminal equipment.
The packet switching means may use a VC in the common VP or in the common VC group when an outgoing call occurs from the user terminal equipment, or when an incoming call takes place from the external ATM switching network.